Say the Andromeda is crashing with Earth. These are two nearby
galaxies.
In a billion years they will collide and the collision may last 3
billion years.

We have seen many collided galaxies in space. But yoyu take this
miniascule event taking place in a close proximity, and wonder how
could
the Universe be only 13.2 billion years old. Something doesn't nake
sense.

Allways a mistake to generalize about a large system from one event

Yeah but its always the flat Earth and I am always right.